U.S. patent application number 09/790391 was filed with the patent office on 2003-10-09 for vacuum pump and shock absorber for artificial limb.
Invention is credited to Caspers, Carl A..
Application Number | 20030191539 09/790391 |
Document ID | / |
Family ID | 25150541 |
Filed Date | 2003-10-09 |
United States Patent
Application |
20030191539 |
Kind Code |
A1 |
Caspers, Carl A. |
October 9, 2003 |
VACUUM PUMP AND SHOCK ABSORBER FOR ARTIFICIAL LIMB
Abstract
A weight-actuated vacuum pump and shock absorber for an
artificial limb. Ambulation causes the vacuum pump, under the
influence of the wearer's body weight, to draw air out of the
artificial limb socket cavity, producing a vacuum within the
socket. The vacuum pulls the residual limb into firm and total
contact with the socket and prevents the loss of fluids in the
residual limb. A shock absorber acts in conjunction with the vacuum
pump to reduce the shock of impact on the wearer caused by
ambulation.
Inventors: |
Caspers, Carl A.; (Avon,
MN) |
Correspondence
Address: |
BRIGGS AND MORGAN, P.A.
2400 IDS CENTER
MINNEAPOLIS
MN
55402
US
|
Family ID: |
25150541 |
Appl. No.: |
09/790391 |
Filed: |
February 21, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09790391 |
Feb 21, 2001 |
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09534274 |
Mar 23, 2000 |
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6554868 |
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09534274 |
Mar 23, 2000 |
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09325297 |
Jun 3, 1999 |
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Current U.S.
Class: |
623/35 ;
623/34 |
Current CPC
Class: |
A61F 2002/5052 20130101;
A61F 2002/5053 20130101; A61F 2002/5015 20130101; A61F 2/74
20210801; A61F 2/742 20210801; A61F 2002/5032 20130101; A61F
2002/7818 20130101; A61F 2210/0057 20130101; A61F 2/5044 20130101;
A61F 2/601 20130101; A61F 2/7812 20130101; A61F 2002/607 20130101;
A61F 2013/15528 20130101; A61F 2002/7655 20130101; A61F 2002/704
20130101; A61F 2002/802 20130101; A61F 2/80 20130101; A61F 2/7843
20130101; A61F 2/644 20130101; A61F 2002/5003 20130101; A61F
2002/805 20130101; A61F 2/5046 20130101; A61F 2002/5033
20130101 |
Class at
Publication: |
623/35 ;
623/34 |
International
Class: |
A61F 002/80; A61F
002/60 |
Claims
What is claimed:
1. A weight-activated vacuum pump and shock absorber for an
artificial limb, the artificial limb having a socket adapted to
receive the residual limb into a cavity therein and adapted to pull
the residual limb into firm and total contact with the socket under
the influence of vacuum and adapted to prevent the loss of fluids
in the residual limb by opposing such loss with vacuum, the vacuum
pump and shock absorber comprising: a) a cylinder having a first
wall, a second wall, and side walls; b) a piston reciprocating
within the cylinder; c) a seal between the piston and the cylinder
side walls; d) a vacuum chamber formed by the piston, the seal, the
side walls and the first wall; e) an intake port connecting the
vacuum chamber to the socket cavity; and f) an exhaust port
connecting the vacuum chamber to atmosphere.
2. The vacuum pump of claim 1, further comprising a shock
absorber.
3. The vacuum pump of claim 2, wherein the shock absorber further
comprises a spring adapted to be compressed under the weight of the
wearer of the artificial limb.
4. The vacuum pump of claim 2, wherein the shock absorber further
comprises a compression chamber filled with a fluid, the fluid in
the compression chamber being adapted to be compressed by the
piston under the weight of the wearer of the artificial limb.
5. The vacuum pump of claim 4, wherein the compression chamber is
formed by the piston, the seal, the side walls and the second
wall.
6. The vacuum pump of claim 4, wherein the fluid is air.
7. The vacuum pump of claim 2, wherein the shock absorber further
comprises a compression chamber filled with a fluid, an overflow
chamber, and a valve connecting the compression chamber to the
overflow chamber, wherein the fluid in the compression chamber is
forced into the overflow chamber by the piston under the weight of
the wearer of the artificial limb.
8. The vacuum pump of claim 7, wherein the fluid is hydraulic
fluid.
9. The vacuum pump of claim 4, wherein the maximum compression of
the fluid in the compression chamber is adjustable by the wearer of
the artificial limb.
10. The vacuum pump of claim 7, wherein the rate of flow of fluid
from the compression chamber to the overflow chamber is adjustable
by the wearer of the artificial limb.
11. A weight-activated vacuum pump and shock absorber for an
artificial limb, the artificial limb having a socket adapted to
receive the residual limb into a cavity therein and adapted to pull
the residual limb into firm and total contact with the socket under
the influence of vacuum and adapted to prevent the loss of fluids
in the residual limb by opposing such loss with vacuum, the vacuum
pump and shock absorber comprising: a) a cylinder having a first
wall, a second wall, and side walls; b) a piston reciprocating
within the cylinder; c) a seal between the piston and the cylinder
side walls; d) a vacuum chamber formed by the piston, the seal, the
side walls and the first wall; e) an intake port connecting the
vacuum chamber to the socket cavity; f) an exhaust port connecting
the vacuum chamber to atmosphere; and g) a shock absorber.
12. The vacuum pump of claim 11, wherein the shock absorber further
comprises a spring adapted to be compressed under the weight of the
wearer of the artificial limb.
13. The vacuum pump of claim 11, wherein the shock absorber further
comprises a compression chamber filled with a fluid, the fluid in
the compression chamber being adapted to be compressed by the
piston under the weight of the wearer of the artificial limb.
14. The vacuum pump of claim 13, wherein the compression chamber is
formed by the piston, the seal, the side walls and the second
wall.
15. The vacuum pump of claim 13, wherein the fluid is air.
16. The vacuum pump of claim 11, wherein the shock absorber further
comprises a compression chamber filled with a fluid, an overflow
chamber, and a valve connecting the compression chamber to the
overflow chamber, wherein the fluid in the compression chamber is
forced into the overflow chamber by the piston under the weight of
the wearer of the artificial limb.
17. The vacuum pump of claim 16, wherein the fluid is hydraulic
fluid.
18. The vacuum pump of claim 13, wherein the maximum compression of
the fluid in the compression chamber is adjustable by the wearer of
the artificial limb.
19. The vacuum pump of claim 16, wherein the rate of flow of fluid
from the compression chamber to the overflow chamber is adjustable
by the wearer of the artificial limb.
Description
[0001] This is a continuation-in-part for previously filed and
co-pending application Ser. No. 09/534,274 filed Mar. 23, 2000,
which is a continuation of application Ser. No. 09/325,297, filed
Jun. 3, 1999 and titled "Hypobarically-Controlled Socket for
Artificial Limb."
BACKGROUND OF THE INVENTION
[0002] The present invention relates to prosthetic devices and more
particularly to various embodiments of a vacuum pump and shock
absorber for an artificial limb.
[0003] An amputee is a person who has lost part of an extremity or
limb such as a leg or arm which commonly may be termed as a
residual limb. Residual limbs come in various sizes and shapes with
respect to the stump. That is, most new amputations are either
slightly bulbous or cylindrical in shape while older amputations
that may have had a lot of atrophy are generally more conical in
shape. Residual limbs may further be characterized by their various
individual problems or configurations including the volume and
shape of a stump and possible scar, skin graft, bony prominence,
uneven limb volume, neuroma, pain, edema or soft tissue
configurations.
[0004] Referring to FIGS. 1 and 2, a below the knee residual limb
10 is shown and described as a leg 12 having been severed below the
knee terminating in a stump 14. In this case, the residual limb 10
includes soft tissue as well as the femur 16, knee joint 18, and
severed tibia 20 and fibula 22. Along these bone structures
surrounded by soft tissue are nerve bundles and vascular routes
which must be protected against external pressure to avoid
neuromas, numbness and discomfort as well as other kinds of
problems. A below the knee residual limb 10 has its stump 14
generally characterized as being a more bony structure while an
above the knee residual limb may be characterized as including more
soft tissue as well as the vascular routes and nerve bundles.
[0005] Referring to FIG. 2, amputees who have lost a part of their
arm 26, which terminates in a stump 28 also may be characterized as
having vascular routes, nerve bundles as well as soft and bony
tissues. The residual limb 10 includes the humerus bone 30 which
extends from below the shoulder to the elbow from which the radius
34 and ulna 36 bones may pivotally extend to the point of
severance. Along the humerus bone 30 are the biceps muscle 38 and
the triceps muscle 40 which still yet may be connected to the
radius 34 and the ulna, 36, respectively.
[0006] In some respects, the residual limb amputee that has a
severed arm 26 does not have the pressure bearing considerations
for an artificial limb but rather is concerned with having an
artificial limb that is articulable to offer functions typical of a
full arm, such as bending at the elbow and grasping capabilities.
An individual who has a paralyzed limb would also have similar
considerations wherein he or she would desire the paralyzed limb to
having some degree of mobility and thus functionality.
[0007] Historically, artificial limbs typically used by a leg
amputee were for the most part all made out of wood such as an
Upland Willow. The limbs were hand carved with sockets for
receiving the stump 14 of the residual limb 10. Below the socket
would be the shin portion with the foot below the shin. These
wooden artificial limbs were covered with rawhide which often were
painted. The sockets of most wood limbs were hollow as the limbs
were typically supported in the artificial limb by the
circumferential tissue adjacent the stump 14 rather than at the
distal end of the stump 14.
[0008] Some artificial limbs in Europe were also made from forged
pieces of metal that were hollow. Fiber artificial limbs were also
used which were stretched around a mold after which they were
permitted to dry and cure. Again, these artificial limbs were
hollow and pretty much supported the residual limb about the
circumferential tissue adjacent the stump 14.
[0009] All of these various artificial limbs have sockets to put
the amputee's stump 14 thereinto. There are generally two
categories of sockets. There are hard sockets wherein the stump
goes right into the socket actually touching the socket wall
without any type of liner or stump sock. Another category of
sockets is a socket that utilizes a liner or insert. Both
categories of sockets typically were opened ended sockets where
they had a hollow chamber in the bottom and no portion of the
socket touched the distal end of the stump 14. So, the stump was
supported about its circumferential sides as it fits against the
inside wall of the sockets.
[0010] These types of sockets caused a lot of shear force on the
stump 14 as well as had pressure or restriction problems on the
nerve bundles and vascular flow of fluid by way of the
circumferential pressure effect of the socket on the limb. This
pressure effect could cause a swelling into the ends of the socket
where an amputee may develop severe edema and draining nodules at
the end of their stump 14.
[0011] With time, prosthetists learned that by filling in the
socket's hollow chamber and encouraging a more total contact with
the stump and the socket, the swelling and edema problems could be
eliminated. However, the problematic tissue configurations, such as
bony prominences, required special consideration such as the
addition of soft or pliable materials to be put into the
socket.
[0012] Today, most artificial limbs are constructed from thermoset
plastics such as polyester resins, acrylic resins, polypropylenes
and polyethylenes, which are perhaps laminated over a nylon
stockinette which also may be impregnated by the various
resins.
[0013] In the past, most artificial limbs were suspended from the
amputee's body by some form of pulley, belt or strap suspension
often used with various harnesses and perhaps leather lacers or
lacings. Another method of suspending artificial limbs is known as
the wedge suspension wherein an actual wedge is built into the
socket which is more closed at its top opening. The wedge in the
socket cups the medial femoral condyle or knuckle at the abductor
tubical. Yet another form of suspension is referred to as the
shuttle system or a mechanical hookup or linkup wherein a thin
suction liner is donned over the stump that has a docking device on
the distal end which mechanically links up with its cooperative
part in the bottom of the socket chamber. Sleeve suspensions were
also used wherein the amputee may use a latex rubber tube which
forms into a rubber-like sleeve which would be rolled on over both
the top of the artificial limb and onto the amputee's thigh. The
sleeve suspensions have been used in combination with other forms
of suspensions techniques.
[0014] Both the use of a positive pressure system and the use of a
negative pressure system (or hypobaric closed chamber) have been
utilized in the field of prosthetics. At one time, for pressure
systems "inflatable inner tubes" were used to fit into sockets.
Presently, there are pneumatic "bags" which are strategically
placed over what people consider to be good weight-bearing areas to
increase pressure to help accommodate for volume changes within the
socket.
[0015] The problem with this is that it is a very specific pressure
and creates atrophy and loss of tissue dramatically over these high
pressure areas. None of these systems employs positive pressure
distributed over the total contact area between the residual limb
and the artificial limb socket to accommodate volume changes within
the socket.
[0016] The negative pressure aspects have been utilized for a
closed chamber in that a socket is donned by pulling in with a
sock, pulling the sock out of the socket and then closing the
opening with a valve. This creates a seal at the bottom and the
stump is held into the socket by the hypobaric seal. However, there
are no systems that employ a negative pressure produced by a vacuum
pump to lock the residual limb to the artificial limb.
[0017] The older systems were initially started in Germany. They
were an open-ended socket, meaning there was an air chamber in the
bottom of the socket. This did not work particularly well because
it would cause swelling of the residual limb into the chamber
created by the negative draw of suspending the weight of the leg
and being under a confined area. This would lead to significance
edema which would be severe enough to cause stump breakdown and
drainage.
[0018] It was later discovered in America that total contact was
essential between the residual limb and the socket and once you had
total contact the weight was distributed evenly or the suspension
was distributed over the whole surface of the limb rather than just
over the open chamber portion of the socket.
[0019] The human body as a whole is under approximately one
atmosphere of pressure at sea level. It keeps and maintains a
normal fluid system throughout the body. When an amputee dons a
prosthesis and begins taking the pressures of transmitting the
weight of the body through the surface area of the residual limb to
the bone, there is increased pressure on the residual limb equal to
one atmosphere plus whatever additional pressures are created by
weight bearing. This increased pressure causes the eventual loss of
fluids within the residual limb to the larger portion of the body
which is under less pressure. This loss of fluids causes the volume
of the residual limb to decrease during the day. It varies from
amputee to amputee, but it is a constant among all amputees and the
more "fleshy" and the softer the residual limb, the more volume
fluctuation there will be. The greater the weight and the smaller
the surface area, the greater the pressures will be and the more
"swings" there will be in fluids. In the past, the amputee had to
compensate for this volume decrease by removing the artificial limb
and donning additional stump socks to make up for the decreased
residual limb volume.
[0020] Japanese patent JP 7-155343 A discloses a pump to apply
pressure or suction to an artificial limb socket, in order to
attach the artificial limb to the limb stump. However, this patent
does not disclose the use of vacuum to draw the residual limb into
firm and total contact with the socket, nor does it disclose the
use of vacuum to prevent loss of residual limb fluids due to
weight-bearing pressures.
[0021] U.S. Pat. No. 5,888,230 discloses the use of a vacuum pump
connected between the limb and a liner. However, this invention is
essentially inoperable because the liner will conform to the stump
at all times, by an interference fit, so that there is no space
between the residual limb and the liner against which to draw a
vacuum. In any case, the patent does not disclose application of
vacuum to the socket cavity in such a manner as to draw the
residual limb firmly and totally against the interior of the
socket. Instead, the patent discloses the use of shims between the
liner and the socket. Without total contact between the residual
limb and the socket, the limb may swell into the space between the
limb and the socket. Also, the patent does not disclose the use of
vacuum to prevent reduction in volume of the artificial limb due to
weight-bearing pressures.
[0022] U.S. Pat. No. 5,549,709 discloses several embodiments of a
hypobarically-controlled artificial limb. However, all of these
embodiments required two sockets: an outer socket and an inner
socket. Applicant has found that the present invention offers
improved performance without the requirement for two sockets. A
single socket works equally well or better than two sockets.
[0023] Also, it has been found that it is essentially impossible to
maintain a perfect, airtight seal between the residual limb and the
sockets disclosed in U.S. Pat. No. 5,549,709, with the result that
slow air leakage into the sockets diminishes the vacuum in the
sockets. With the reduction in vacuum, the beneficial effects of
the vacuum also slowly diminish. Consequently, there is a need for
a means for maintaining the vacuum in the socket cavity in the
presence of some air leakage past the seal.
[0024] While some of these devices addressed some of the problems
associated with prosthetics, none of the artificial limbs, liners
and socket, individually or in combination, offered a prosthesis
that presented a total contact relationship with the residual limb;
absorbed and dissipated shear, shock and mechanical forces
transmitted to the limb tissues by the artificial limb; controlled
residual limb volume; and used negative pressure as a locking
device to hold the residual limb into the socket.
[0025] There is a need for a vacuum pump and shock absorber for an
artificial limb to maintain the vacuum in the cavity in the
presence of some air leakage past the seal.
SUMMARY OF THE INVENTION
[0026] A principal object and advantage of the present invention is
that it includes a weight-activated vacuum pump that automatically
maintains vacuum in the cavity of the artificial limb socket as the
wearer walks on the artificial limb.
[0027] Another principle object and advantage of the present
invention is that it provides a shock absorbing function.
[0028] Another principle object and advantage of the present
invention is that the amount of shock absorption is adjustable by
the wearer.
[0029] Another principle object and advantage of the present
invention is that it provides an anti-rotation function.
[0030] Another principle object and advantage of the present
invention is that the degree of anti-rotation is adjustable by the
wearer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a side elevational view of the tissue and skeletal
structure of an amputee's residual limb;
[0032] FIG. 2 is a side elevational view of a residual limb in the
form of an amputated arm showing the skeletal and muscular
structure of the residual limb;
[0033] FIG. 3 is an exploded elevational view of the residual limb
donning the polyurethane sleeve, stretchable nylon sleeve, liner,
nylon sheath and socket of an artificial limb;
[0034] FIG. 4 is a cross-section of the artificial limb in FIG. 3,
which is a first embodiment of the artificial limb;
[0035] FIG. 5 is a cross-section of the artificial limb similar to
FIG. 4, showing a second embodiment of the artificial limb;
[0036] FIG. 6 is the same as FIG. 5, but showing compression of the
inner socket under the influence of positive air pressure;
[0037] FIG. 7 is a cross-section of the artificial limb showing a
third embodiment of the artificial limb;
[0038] FIG. 8 is a cross-section of the artificial limb showing a
fourth embodiment of the artificial limb;
[0039] FIG. 9 is an elevational view of the polyurethane sleeve and
second stretchable nylon sleeve rolled over the socket and residual
limb with clothing shown in broken outline;
[0040] FIG. 10 is a cross-section of the artificial limb showing a
fifth embodiment of the artificial limb;
[0041] FIG. 11 is a cross-section of the artificial limb showing a
sixth embodiment of the artificial limb;
[0042] FIG. 12 is a detailed view of the vacuum mechanism in FIG. 1
1;
[0043] FIG. 13 is a cross-section of the artificial limb showing a
seventh embodiment of the artificial limb;
[0044] FIG. 14 is a detailed view of the vacuum mechanism and
suspension sleeve of FIG. 13;
[0045] FIG. 15 is a cross-section of the artificial limb showing an
eighth embodiment of the artificial limb;
[0046] FIG. 16 is a cross-section of the artificial limb showing a
ninth embodiment of the artificial limb;
[0047] FIG. 17 is an exploded perspective view of a first
embodiment of a weight-activated vacuum pump and shock
absorber;
[0048] FIG. 18 is a diagrammatic exploded view of a first
embodiment of a weight-activated vacuum pump and shock
absorber;
[0049] FIG. 19A is a side elevational view of a first embodiment of
a weight-activated vacuum pump and shock absorber;
[0050] FIG. 19B is a cross-section along the lines 19B of FIG.
19A;
[0051] FIG. 20 is a cross-section along the lines 20 of FIG.
19B;
[0052] FIG. 21 is a cross-section along the lines 21 of FIG.
19B;
[0053] FIG. 22 is a detailed cross-section of a first embodiment of
a weight-activated vacuum pump and shock absorber in the unweighted
state;
[0054] FIG. 23 is the same as FIG. 22, except that the wearer's
weight is being applied to the pylon of the artificial limb;
[0055] FIG. 24 is the same as FIG. 23, with the wearer's weight
fully applied to the pylon of the artificial limb;
[0056] FIG. 25 is the same as FIG. 23, with the wearer's weight
being removed from the pylon of the artificial limb;
[0057] FIG. 26 is a top perspective view of a second embodiment of
a weight-actuated vacuum pump and shock absorber, with some
structure removed;
[0058] FIG. 27A is a side perspective view of a second embodiment
of a weight-actuated vacuum pump and shock absorber. FIG. 27B is a
schematic of the intake/exhaust port and one-way valves of this
embodiment;
[0059] FIG. 28 is a perspective view of some internal structure of
a second embodiment of a weight-actuated vacuum pump and shock
absorber; and
[0060] FIG. 29A is a top plan view of a second embodiment of a
weight-actuated vacuum pump and shock absorber. FIG. 29B is a
cross-section along the lines 29B of FIG. 29A.
[0061] FIG. 30 is a perspective view of a third embodiment of a
weight-actuated vacuum pump and shock absorber.
[0062] FIG. 31 is a cross-section showing the internal structure of
the third embodiment of FIG. 30, showing the pump without any of
the wearer's weight applied to it.
[0063] FIG. 32 is the same as FIG. 31, but with the wearer's weight
applied.
[0064] FIG. 33 is the same as FIG. 32, but with the wearer's weight
being removed.
[0065] FIG. 34 is a side elevational view of the pump of the third
embodiment in place on an artificial limb.
[0066] FIG. 35 is a cross-section showing the internal structure of
a fourth embodiment of a weight-actuated vacuum pump and shock
absorber without any of the wearer's weight applied to it.
[0067] FIG. 36 is the same as FIG. 35, but with the wearer's weight
beginning to be applied.
[0068] FIG. 37 is the same as FIG. 36, but with all of the wearer's
weight applied.
[0069] FIG. 38 is the same as FIG. 37, but with the wearer's weight
being removed.
[0070] FIG. 39A is a side elevational view of an artificial foot,
employing the fourth embodiment of a weight-actuated vacuum pump
and shock absorber
[0071] FIG. 39B is the same as FIG. 39A, rotated 90 degrees.
[0072] FIG. 40 is a side elevational view of an artificial limb for
an above-the-knee amputee, with the fourth embodiment of the
weight-actuated vacuum pump and shock absorber.
[0073] FIG. 41 is a front elevational view, similar to FIG. 40.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0074] FIG. 3 shows a hypobarically-controlled artificial limb 50.
The hypobarically-controlled artificial limb 50 includes an outer
socket 52, shin 54, and foot 56. The outer socket 52 has a volume
and shape to receive a substantial portion of the residual limb 14
with a space 58 therebetween.
[0075] A first embodiment of the hypobarically-controlled
artificial limb 50 is shown in FIG. 4. The hypobarically-controlled
artificial limb 50 further includes a flexible inner socket 60 with
a cavity 62 with a volume and shape for receiving a substantial
portion of the residual limb 14 and fitting in the space 58 between
the outer socket 52 and the residual limb 14. The inner socket 60
has an inner surface 64 opposing the residual limb 14 and an outer
surface 66 opposing the outer socket 52.
[0076] A vacuum source 70 may conveniently be attached to the shin
or pylon 54. The vacuum source 70 may preferably be a mechanical or
motor-driven pump 72. The vacuum source 70 is connected to a power
source 83, which may be a battery.
[0077] A vacuum valve 74 is suitably connected to the vacuum source
70. The vacuum valve 74 may preferably be disposed on the outer
socket 52. A vacuum tube 76 connects the vacuum valve 74 to the
cavity 62. It will be seen that the vacuum source will cause the
residual limb 14 to be drawn into firm contact with the inner
surface 64 of the inner socket 60.
[0078] The hypobarically-controlled artificial limb 50 also
includes a regulator means 80 for controlling the vacuum source 70.
Preferably, the regulator means 80 may be a digital computer 82.
Alternately, the regulator means may be a vacuum regulator. The
regulator means 80 is connected to a power source 83, which may be
a battery.
[0079] A seal means 84 makes an airtight seal between the residual
limb 14 and the outer socket 52. Preferably, the seal means 84 is a
nonfoamed, nonporous polyurethane suspension sleeve 86 which rolls
over and covers the outer socket 52 and a portion of the residual
limb 14. Alternatively, the seal means 84 may be any type of seal
which is airtight.
[0080] The hypobarically-controlled artificial limb 50 may also
include a thin sheath 90 between the residual limb 14 and the inner
surface 64 of the inner socket 60. As vacuum is applied to the
cavity 62, the sheath 90 will allow the vacuum to be evenly applied
throughout the cavity 62. Without the sheath 90, the residual limb
14 might "tack up" against the inner surface 64 and form a seal
which might prevent even application of the vacuum to the cavity
62. The sheath 90 may also be used to assist the amputee into a
smooth and easy fitting into the inner socket 60. The sheath 90 is
preferably made of thin knitted nylon.
[0081] The hypobarically-controlled artificial limb 50 may also
include a nonfoamed, nonporous polyurethane liner 92 receiving the
residual limb 14 and disposed between the sheath 90 and the
residual limb 14. The liner 92 provides a total-contact hypobaric
suction, equal weight distribution socket liner. The liner 92
readily tacks up to the skin of the residual limb 14 and provides
total contact with the limb 14. The liner 92 absorbs and dissipates
shock, mechanical and shear forces typically associated with
ambulation.
[0082] The hypobarically-controlled artificial limb 50 may also
include a stretchable nylon second sleeve 94 for rolling over and
covering the suspension sleeve 86 to prevent clothing from sticking
to and catching the suspension sleeve 86.
[0083] Referring to FIG. 3, the polyurethane tubular sleeve 86 may
be appreciated alone and in combination with the urethane liner 92
together with the optional nylon sheath 90 and second stretchable
nylon sleeve 94.
[0084] More specifically, the amputee takes the stretchable nylon
second sleeve 94, suitably made of a spandex-like material and
rolls it up over the stump 14 to the upper portions of the residual
limb suitably as the thigh of a leg 12. Next, the polyurethane
sleeve 86 is also rolled upwardly over the residual limb 10.
Thereafter, the liner 92 is optionally donned.
[0085] Next, the amputee may optionally utilize the nylon sheath 90
which is suitably of a non-stretching, thin, friction reducing
nylon. As stated, this sheath 90 optionally may be used to assist
the amputee into a smooth and easy fitting into the inner socket
60. Alternatively, the sheath 90 may be avoided and the liner 92
simply inserted into the inner socket 60 of the artificial limb
50.
[0086] Next, the amputee simply grasps the rolled over portion of
the polyurethane sleeve 86 and rolls it over a substantial portion
of the outer socket 52. The sleeve 86 makes an airtight seal
between the residual limb 14 and the outer socket 52.
[0087] As can be appreciated, the polyurethane sleeve 86 is tacky.
Consequently, the stretchable nylon second sleeve 94 may be
utilized and rolled over the polyurethane sleeve 86.
[0088] The amputee then sets the regulator means 80 to cause the
vacuum source 70 to apply vacuum through the vacuum valve 74 and
vacuum tube 76 to the cavity 62. Enough vacuum is applied to cause
the residual limb (with optional coverings) to be drawn firmly
against the inner surface 64 of the inner socket 60, which is
flexible. The vacuum source 70 may preferably maintain a vacuum in
the range of 0 to 25 inches of mercury (ideally fifteen to twenty
inches).
[0089] It will be seen that the vacuum within the inner socket 60
will cause the hypobarically-controlled artificial limb 50 to be
suspended from the residual limb 14. The vacuum will lock the
residual limb 14 into the inner socket 60 without causing swelling
of the residual limb into the socket, because of the total contact
of the residual limb 14 with the inner socket 60. That is, there is
no open chamber between the residual limb 14 and the inner socket
60 which would draw on the residual limb.
[0090] As the volume of the residual limb 14 decreases during the
day due to weight-bearing pressures, the regulator means 70 may
appropriately adjust the vacuum source 70 to draw the residual limb
14 more firmly against the inner socket 60 and thus compensate for
the loss of residual limb volume. The vacuum may also partially
oppose the loss of fluids from the residual limb caused by
weight-bearing pressures.
[0091] A second embodiment of the hypobarically-controlled
artificial limb 50 is shown in FIGS. 5 and 6. The second embodiment
of the hypobarically-controlled artificial limb 50 is as described
above, with the exception that the inner socket 60A is compressible
as well as being flexible. Instead of a vacuum source, the second
embodiment has a positive air pressure source 100, which may
preferably be a motor-driven pump 102. The regulator means 80,
which may be a digital computer 82, controls the positive air
pressure source 100. The regulator means and positive air pressure
source 100 are connected to a power source 83, which may be a
battery. A positive pressure valve 104 connects the space 58 to the
positive air pressure source 100, for compressing the inner socket
60A as the volume of the residual limb decreases.
[0092] It will be seen that as the volume of the residual limb 14
decreases during the day due to weight-bearing pressures, the
regulator means 80 may control the positive air pressure source 100
to cause air pressure to compress the inner socket 60A to
compensate for the decreased volume of the residual limb, as shown
in FIG. 6.
[0093] A third embodiment of the hypobarically-controlled
artificial limb 50 is shown in FIG. 7. The third embodiment is a
combination of the first and second embodiments described
above.
[0094] The mechanical motor-driven pump 72 may act as both the
vacuum source 70 and the positive air pressure source 100. The
regulator means 80, vacuum source 70 and positive air pressure
source 100 are connected to a power source 83, which may be a
battery.
[0095] The vacuum source 70, under control of the regulator means
80, will compensate for reduced residual limb volume up to a
certain point. From that point on, the regulator means 80 will
cause the positive air pressure source 100 to further compensate
for reduced residual limb volume as described above. The third
embodiment thus uses both vacuum and positive air pressure working
together to lock the residual limb 14 into the inner socket 60 and
reduce socket volume to compensate for fluid loss in the residual
limb 14. The exact point at which the changeover is made between
vacuum compensation and positive air pressure compensation is
controlled by the regulator means 80, which as described may be a
digital computer appropriately programmed for the socket
environment.
[0096] A fourth embodiment of the hypobarically-controlled
artificial limb 50 is shown in FIG. 8. The fourth embodiment is
like the first embodiment, but includes two vacuum valves: a first
vacuum valve 106 and a second vacuum valve 110, both connected to
the vacuum source 70. The first vacuum valve 106 connects the
vacuum source 70 to the space 58. The space 58 contains a
semi-compressible material 108, such as polystyrene beads, as
disclosed in U.S. Pat. No. 4,828,325, herein incorporated by
reference.
[0097] To don the artificial limb 50, the amputee proceeds as
described above. After inserting the residual limb 14 (with
optional coverings) into the inner socket 60B, which is both
compressible and expandable, and rolling the suspension sleeve 86
over the outer socket 52, the amputee activates the regulator means
80, causing the vacuum source 70 to apply a vacuum to the space 58.
This causes the material 108 to lock mechanically together into a
rigid mass, conforming to the shape of the residual limb 14. The
inner socket 60B may expand slightly under the weight of the
residual limb 14 and under the influence of vacuum.
[0098] It will be seen that the semi-compressible molding material
108 can be molded to the contours of the residual limb 14 without
using a custom-building process to produce a custom socket. The
outer socket 52 may appropriately occur in standard sizes, such as
small, medium, and large. The inner socket 60B may also occur in
standard sizes such as small, medium, and large. Adaptation of the
inner socket 60B to the contours of the residual limb 14 occurs
through solidifying the material 108 under the influence of
vacuum.
[0099] The second vacuum valve 110 connects the vacuum source 70 to
the cavity 62 as previously described, for locking the residual
limb 14 into the inner socket 60B.
[0100] The fourth embodiment may also include a positive air
pressure source 100 as previously described, to adjust the size of
the inner socket 60B to compensate for decreased residual limb
volume.
[0101] The fourth embodiment may also include a thin sheath 90,
liner 92, and second sleeve 94, as previously described.
[0102] The positive air pressure source 100 may also be used for
shock absorption and a dynamic response in the ankle and foot
sections of the artificial limb 50, by means of a connection
120.
[0103] A fifth embodiment of the hypobarically-controlled
artificial limb 50 is shown in FIG. 10. This embodiment is the same
as the first embodiment shown in FIG. 4, with some changes. First,
vacuum source 71 may be a hand-operated vacuum pump 71 which may
remove air from the cavity 62 down to approximately 15-25 inches of
mercury. A suitable hand-operated vacuum pump is marketed under the
trademark MITY VAC II.RTM. by Neward Enterprises, Inc. of
Cucamonga, Calif.
[0104] The fifth embodiment also includes the seal means 84 which
preferably consists of a non-foamed, nonporous polyurethane
suspension sleeve 86 for rolling over and covering a portion of the
residual limb 14. A portion of the seal means 86 is adapted to be
disposed between the outer socket 52 and the inner socket 60. The
sleeve may be made of any of a variety of air-impervious
elastomers.
[0105] The fifth embodiment, shown in FIG. 10 also includes a
mechanical interlock 67, 59 for interlocking the inner socket 62
with the outer socket 52. Preferably, the mechanical interlock
consists of a first detent 67 in the inner socket 62 and a second
detent 59 in the outer socket 52. The first detent 67 engages the
second detent 59 to lock the inner socket 60 into the outer socket
52.
[0106] A sixth embodiment of the hypobarically-controlled
artificial limb of the present invention is shown in FIGS. 11 and
12. The sixth embodiment is like the first embodiment shown in FIG.
4, with some changes.
[0107] First, the inner socket is specifically intended to be
removably from the outer socket. To provide a positive mechanical
connection between the inner socket and outer socket and yet allow
the inner socket to be easily removed, the sixth embodiment
includes a mechanical interlock 103 engaging the inner socket 60
and the outer socket 52. Preferably, the mechanical interlock may
be an extension 104 which is attached to the inner socket 60 and a
docking device 106 attached to the outer socket 52 and receiving
the extension 104, and a locking mechanism 105 engaging the
extension 104 and the docking device 106.
[0108] The extension may be any sort of protrusion from the inner
socket, such as a bulge or tab. Preferably, the extension 104
comprises a shuttle pin 108.
[0109] The locking mechanism may be any sort of member which
engages both the extension 104 and the docking device 106, such as
a screw, wire, or pin. Preferably, the locking mechanism 105
comprises a second pin 110 which extends outside the outer socket
52 as to be accessible.
[0110] Second, the sixth embodiment includes two thin sheaths,
rather than one. A first inner sheath 90 may preferably be disposed
between the residual limb 14 and the inner surface 64 of the inner
socket 60. As vacuum is applied to the cavity 62, the inner sheath
90 will allow the vacuum to be evenly applied throughout the cavity
62. Without the inner sheath 90, the residual limb 14 might "tack
up" against the inner surface 64 and form a seal which might
prevent even application of the vacuum to the cavity 62. The inner
sheath 90 may also be used to assist the amputee into a smooth and
easy fitting into the inner socket 60.
[0111] An outer sheath 93 is preferably disposed between the
suspension sleeve 86 and the inner socket 60, thereby preventing
the suspension sleeve from tacking to the inner socket 60. Such
tacking would cause friction between the inner socket 60 and the
sleeve 86 which would cause the sleeve to wear out. Such tacking
might also cause restrictions in the movement of the residual limb.
The outer sheath 93 also protects the suspension sleeve 86 from
being damaged by friction with the inner socket 60.
[0112] The sixth embodiment also preferably includes an adhesive
pressure tape 95 adapted to cover the outer sheath 93, suspension
sleeve 86, and the second sleeve 94 and sealing the outer sheath
93, suspension sleeve 86, and the second sleeve 94 to the inner
socket 60. The tape 95 locks all of these layers to the inner
socket so that they do not come loose during movement.
[0113] In the sixth embodiment, the suspension sleeve 86 goes
between the inner socket 60 and the outer socket 52, so that the
sleeve 86 is protected from damage.
[0114] In the sixth embodiment, the inner socket 60 has a rigid
lower portion 98 and a substantially flexible upper portion 96. The
rigid lower portion assists in weight-bearing while the
substantially flexible upper portion allows for movement of the
residual limb 14. As the knee is bent from fully straight to fully
flexed, the width of the knee changes rather significantly and in a
hard, non-flexible socket brim, there can be excessive pressure on
the residual limb 14. The substantially flexible upper portion 96
makes the artificial limb 50 more comfortable and more adaptive to
these changes. For the same reason, the outer socket 52 has a rigid
lower portion 102 and a substantially flexible upper portion
100.
[0115] Preferably, the top edge of the inner socket 60 is below the
top edge of the outer socket 52 so that the sleeve 86 is protected
from impact. Preferably, the top edge of the inner socket 60 may be
{fraction (3/16)} inch below the top edge of the outer socket
52.
[0116] The sixth embodiment includes extensive modifications to the
vacuum system.
[0117] First, a vacuum fitting 78 has been added to the inner
socket 60 to attach the vacuum tube 76. The vacuum fitting 78
allows the attachment of a vacuum sensor 79 adapted to sense the
amount of vacuum in the cavity 62 and a sensor lead 81 is attached
to the sensor 79 connecting the sensor 79 to the regulator means
80, thus conveying the sensed vacuum to the regulator means 80.
[0118] A vacuum valve 74 is placed between the cavity 62 and the
vacuum source 70 to maintain vacuum in the cavity 62. Typically,
the vacuum valve 74 is a one-way valve or non-return valve.
[0119] In the sixth embodiment, the vacuum source 70, vacuum tube
76, vacuum valve 74, regulator means 80, and power source 83 are
all attached to the outer socket 52 in the space 58 between the
outer socket 52 and inner socket 60. In this way, these delicate
components are protected against being damaged by impact. Because
of the placement of the regulator means 80 within the outer socket
52, a vacuum control 77 is provided extending outside the outer
socket 52 to allow manual control of the regulator means 80.
[0120] The amputee dons the sixth embodiment in a manner similar to
that earlier described, with some modifications. First, the outer
sheath 93 is put on the residual limb 14 after rolling the
suspension sleeve 86 upward over the residual limb and before
donning the liner 92. After donning the inner sheath 90 over the
liner 92, the amputee inserts the residual limb 14 into the inner
socket 60. Next, the outer sheath 93, suspension sleeve 86, and
second sleeve 94 are rolled down over the inner socket 60, and the
adhesive pressure tape 95 is applied. Next, the wearer sets the
regulator means 80 to an appropriate vacuum level by means of the
vacuum control 77, and connects the vacuum tube 76 to the vacuum
fitting 78. The inner socket 60 is then placed within the outer
socket 52 so that the shuttle pin 108 engages the docking device
106 and the locking pin 110 is set to engage the shuttle pin 108
and the docking device 106, providing a positive mechanical
interlock.
[0121] A seventh embodiment of the hypobarically-controlled
artificial limb of the present invention is shown in FIG. 13. The
seventh embodiment is similar to the sixth embodiment, with some
changes.
[0122] First, the mechanical interlock 103 does not engage the
inner socket 60. Instead, the mechanical interlock engages the
outer socket 52 and the suspension sleeve 86. To accomplish this,
the suspension sleeve 86 covers the entire inner socket 60, and the
suspension sleeve 86 has the extension 104 or shuttle pin 108
embedded in the suspension sleeve at the distal end of the
suspension sleeve, as shown in FIG. 14. Preferably, the extension
104 has a portion 104A embedded in the suspension sleeve. This
portion 104A may be a disk or umbrella 104A. The extension 104 then
engages the docking device 106 as previously described.
[0123] Second, the suspension sleeve 86 is modified to support the
additional weight imposed on the suspension sleeve 86 due to the
outer socket 52 and artificial limb. In particular, the suspension
sleeve 86 is fabricated from a material which allows
circumferential expansion but resists longitudinal stretching under
the weight of the artificial limb. Such a material is described in
U.S. Pat. No. 5,571,208, herein incorporated by reference.
[0124] The sleeve 86 preferably contains fabric threads which may
be oriented circumferentially around the sleeve. The threads
preferably are comprised of double-knit polyurethane. The threads
may also include nylon. The threads permit the sleeve 86 to expand
circumferentially so that the sleeve may be slipped onto the
residual limb 14 and so that the lower portion may be slipped over
the inner socket 52. The threads are preferably connected together
with cross-links, which also may be preferably comprised of
polyurethane. The cross-links and threads form a matrix which
allows circumferential expansion but resists longitudinal
stretching under the weight of the artificial limb. By example, the
sleeve 86 may have a 4-to-1 ratio of circumferential stretch
relative to longitudinal stretch.
[0125] The sleeve 86 may have a portion above the inner socket 52
which is manufactured of material which allows both vertical and
horizontal stretching, to increase flexibility.
[0126] An eighth embodiment of the hypobarically-controlled
artificial limb of the present invention is shown in FIG. 15.
[0127] Unlike earlier embodiments, the artificial limb 50 of the
eighth embodiment has only a single socket 60 rather than inner and
outer sockets and is thus considerably simpler.
[0128] The socket 60 has a volume and shape to receive a
substantial portion of the residual limb 14 with a cavity 62
therebetween.
[0129] A nonfoamed, nonporous polyurethane liner 92 is preferably
adapted to receive the residual limb 14 and to be disposed between
the residual limb 14 and the socket 60.
[0130] A vacuum source 70 is connected to the cavity 62 by a vacuum
valve 78, thereby drawing the residual limb 14 into firm contact
with the socket 60.
[0131] A seal means 84 makes a seal between the residual limb 14
and the socket 60 to minimize air leakage into the cavity 62. It
has been found that it is impossible to make a perfect seal, with
the result that air leakage can occur at rates up to 30 cc per
minute. As air leaks into the cavity 62, it is necessary to
activate the vacuum source 70 to restore vacuum in the cavity.
Furthermore, it has been found that when the vacuum in the cavity
is about 5 inches of mercury, the residual limb may lose up to 6 to
15% of its volume during the day, whereas if the vacuum in the
cavity is 15-25 inches of mercury, the residual limb loses only
about 1% of its volume during the day.
[0132] To minimize the time that the vacuum source, such as a
vacuum pump 72, needs to run to maintain vacuum in the cavity, a
ninth embodiment of the artificial limb 50 is shown in FIG. 16. The
ninth embodiment is the same as the eighth embodiment, but a vacuum
reservoir 110 is added between the vacuum source 70 and the vacuum
valve 78. The vacuum reservoir 110 has a volume substantially
larger than the cavity 62. Suitably, the vacuum reservoir may have
a volume of 2 gallons or 9000 cc while the volume of the cavity 62
may be only about 100 cc or even less.
[0133] It will be seen that as air leaks into the cavity 62, the
air will be pulled into the vacuum reservoir 110, thereby
maintaining the vacuum in the cavity 62.
[0134] When the vacuum in the reservoir 110 reaches a certain
minimum threshold, the vacuum source 70 may be activated to restore
vacuum to the vacuum reservoir 110. The vacuum source 70 may be
activated either manually or by a regulator means (not shown).
[0135] The artificial limb 50 typically includes a shin or pylon 54
and a foot 56, as shown in FIG. 3. Preferably, the vacuum reservoir
110 is attached to the shin 54 between the socket 60 and the foot
56. However, the vacuum reservoir may also be carried separately,
as for example in a backpack. Depending on the placement of the
vacuum reservoir 110, a vacuum tube 76 may be necessary to connect
the vacuum reservoir 110 to the vacuum valve 78.
[0136] If the volume of the vacuum reservoir 110 is about 9000 cc
and air leaks into the cavity 62 at about 75 cc per minute, it will
be seen that the intervals between activation of the vacuum source
70 can be up to about 120 minutes.
[0137] The artificial limb 50 of the eighth and ninth embodiments
may preferably further comprise the following.
[0138] An inner sheath 90 may be adapted to be disposed between the
liner 92 and the socket, to ensure even distribution of vacuum in
the cavity 62, as earlier described. Preferably, the inner sheath
90 may be thin knitted nylon. The sheath 90 may also be affixed to
the outside of the liner 92.
[0139] The seal means 84 is preferably a nonfoamed, nonporous
polyurethane suspension sleeve 86 for rolling over and covering the
socket 60 and a portion of the artificial limb 14, as earlier
described.
[0140] A stretchable nylon second sleeve 94 for rolling over and
covering the suspension sleeve 86 may be added to prevent clothing
from sticking to and catching on the suspension sleeve 86, as
earlier described.
[0141] The vacuum source 70 is preferably a motor or mechanical
driven vacuum pump 72, as earlier described. A vacuum tube 76 may
be necessary to connect the vacuum pump 72 to the vacuum valve 78,
depending on the placement of the vacuum pump 72. istead of using a
vacuum reservoir to maintain the vacuum in the cavity, a
weight-actuated vacuum pump may be employed.
[0142] A first embodiment of a vacuum pump and shock absorber for
an artificial limb is shown in FIGS. 17-25.
[0143] The vacuum pump and shock absorber 200 in one aspect
comprises a housing 210 fixedly attached to the socket 60 and
having a housing top wall 212 and housing side walls 214.
[0144] A cylinder 220 reciprocates within the housing 210 and
sealingly engages the housing side walls 214. The cylinder 220 has
a cylinder top wall 222 and cylinder side walls 224.
[0145] The cylinder 220 is fixedly attached to a cap 230 and the
cap 230 is fixedly attached to the pylon 54.
[0146] A piston 260 is fixedly attached to the housing 210 and
reciprocates within the cylinder 220. Preferably, the piston 260
screws to the housing 210.
[0147] The cylinder top wall 222, cylinder side walls 224, and
piston 260 cooperate to form a first chamber 240.
[0148] The cylinder top wall 222, the housing top wall 212, and the
housing side walls 214 cooperate to form a second chamber 250.
[0149] The piston 260, cylinder side walls 224 and cap 230
cooperate to form a third chamber 241.
[0150] A first valve means 270 connects the first chamber 240 and
the second chamber 250 to the cavity 62 and to the atmosphere. A
second valve means 280 connects the second chamber 250 and the
first chamber 240 to the cavity 62 and to the atmosphere. An
intake/exhaust port 272 is placed between the first valve means 270
and the first chamber 240. An intake port 274 connects the second
chamber 250 to the first valve means 270. An exhaust port 28 4
connects the second chamber 250 to the second valve means 280.
[0151] Preferably, the first valve means 270 may be a three-way
valve 272 and the second valve means 280 is a second three-way
valve 282.
[0152] The weight-activated vacuum pump 200 also preferably
comprises an anti-rotation collar 290 between the cylinder 220 and
the housing 210.
[0153] A first seal 300 is placed between the piston 260 and the
cylinder side walls 224 and a second seal 310 is placed between the
cylinder side walls 224 and the housing side walls 214. Preferably
a first bushing 320 is placed between the cap 230 and the housing
side walls 214 and a second bushing 330 is placed between the
cylinder side walls 224 and the housing side walls 214.
[0154] Preferably, the housing top wall 210 has a hollow core 216
and the piston 260 has a stem 262 slidingly engaging the hollow
core 216. Most preferably, the intake/exhaust port 272 traverses
the stem 262.
[0155] The weight-actuated vacuum pump and shock absorber 200 also
preferably comprises a spring 340 biasing the cylinder 220 toward
the housing top wall 212. Alternatively, compressed air in the
third chamber 241 biases the cylinder 220 toward the housing top
wall 212. An adjustment valve 350 may be provided to vary the
pressure of compressed air between the piston 260 and the cap
230.
[0156] Operation of the first embodiment of the weight-actuated
vacuum pump and shock absorber 200 may now be described.
[0157] FIG. 22 shows the pump 200 in a state where the wearer is
not applying any body weight to the pylon 54, as when sitting down
or at the completion of the swing phase of walking. As can be seen,
the piston 260 abuts the cylinder top wall 220, forced there either
by compressed air in the third chamber 241 or by the spring 340.
The housing 210, which is attached to the piston 260 is at the top
of its travel, with the second chamber 250 expanded to its maximum
volume. The first valve means 270 is closed, sealing off the cavity
62 from the pump 200. The second valve means 280 is open to
atmosphere.
[0158] FIG. 23 shows what happens as the wearer begins to apply
body weight to the pylon 54. The housing 210, attached to the
socket 60 by connector 218, is forced downward, carrying the piston
260 with it. The housing side walls 214 slide along the cylinder
side walls 224. Because the cylinder 220 is fixed to the pylon 54
and does not move, this motion of the housing 210 decreases the
volume of the second chamber 250, causing air to be forced out of
the second chamber 250 through the second valve means 280, as shown
by the dark arrow. Simultaneously, the piston 260 moving downwardly
within the first chamber 240 draws air from the cavity 62 through
the first valve means 270, which has connected the intake/exhaust
port 272 to the cavity 62, producing a vacuum in the cavity 62, as
shown by the light arrows. The motion of the piston 260 will also
compress air in the third chamber 241 between the piston 260 and
the cap 230, providing a shock absorbing function.
[0159] FIG. 24 shows the state where the wearer has placed all of
his body weight on the pylon 54, and the housing 210 and piston 260
are at their maximum travel relative to the cylinder 220. The first
chamber 240 is at its maximum volume and the second chamber 250 is
at its minimum volume. The first valve means 270 has been switched
to connect the second chamber 250 to the cavity 62.
[0160] FIG. 25 shows what happens when the wearer removes his body
weight from the pylon 54, as in the beginning of the swing phase of
ambulation. Under the influence of compressed air in the third
chamber 241 or of the spring 340, the housing 210 and piston 260
are forced upwardly, causing air in the first chamber 240 to be
forced out of the first chamber 240 through the intake/exhaust port
272 and second valve means 280 to atmosphere, as shown by the dark
arrows. Simultaneously, the motion of the housing 210 increases the
volume of the second chamber 250, causing air to be drawn into the
second chamber 250 from the cavity 62 through the first valve means
270, again increasing the amount of vacuum in the cavity 62, as
shown by the light arrows.
[0161] Throughout operation of the pump 200, the anti-rotation
collar 290 prevents the cylinder 220 from rotating within the
housing 210.
[0162] A second embodiment of a weight-actuated vacuum pump and
shock absorber is shown in FIGS. 26-29. Unlike the first
embodiment, which is a double-action pump, the second embodiment is
a single-action pump.
[0163] The weight-actuated vacuum pump 400 comprises a cylinder 410
attached to the pylon 54 and having a first chamber 420 therein. A
piston 430 reciprocates within the first chamber 420. The piston
430 extends outside the cylinder 410 and is fixedly attached to the
socket 62 as by connector 218. Preferably, the cylinder 410 has a
top wall 412 with an aperture 414 therethrough, and the piston 430
has a stem 432 slidingly engaging the aperture 414.
[0164] The piston has a seal 436 along its periphery separating the
first chamber 420 from a second chamber 422 between the piston 430
and the cylinder top wall 412.
[0165] The cylinder top wall 412 may preferably further comprise a
plurality of tubes 416 with a closed end 416A and open end 416B,
the open end 416B facing the socket 60. The stem 432 may have a
plurality of projections 434 slidingly engaging said tubes 416. The
projections 434 sliding within the tubes 416 prevent the stem 432
from rotating within the aperture 414.
[0166] An intake/exhaust port 440 is connected to the first chamber
420. A first one-way valve 450 connects the intake/exhaust port 440
to the cavity 62. A second one-way valve 460 connects the
intake/exhaust port to atmosphere.
[0167] Optionally, a spring 470 biases the piston 430 toward the
socket 60. Alternatively, compressed air in the first chamber 420
biases the piston 430 toward the socket 60. An adjustment valve 480
may be used to vary the pressure of compressed air in the first
chamber 420.
[0168] Applicant has found that the pump may generate up to 22
inches mercury of vacuum in the cavity as the wearer takes seven
steps.
[0169] Operation of the second embodiment may now be described.
[0170] As the wearer brings his body weight to bear on the pylon
54, the piston 430 is forced downwardly within the cylinder 418
against compressed air or the spring 470, providing a
shock-absorbing effect. At the same time, air is drawn into the
second chamber 422 from the cavity 62 through the first one-way
valve 450 and the intake/exhaust port 440, producing a vacuum
within the cavity 62.
[0171] As the wearer removes his body weight from the pylon 54, the
piston 430 is forced upwardly within the first cylinder 410 either
by the spring 470 or compressed air, forcing air out of the second
chamber 422 through the intake/exhaust port 440 and the second
one-way valve 460 to atmosphere.
[0172] A third embodiment of a weight-actuated vacuum pump is shown
in FIGS. 30-34.
[0173] The third embodiment of the pump 510 comprises a cylinder
512 having a first wall 514, a second wall 516 and side walls 518.
The first wall 514, second wall 516, and side walls 518 enclose a
chamber 520 therein, all as best seen in FIG. 31.
[0174] A piston 530 reciprocates within the cylinder 512, in
chamber 520. A seal 532 is placed between the piston 530 and the
cylinder side walls 518.
[0175] As the piston reciprocates within the cylinder 512, a vacuum
chamber 540 is formed by the piston 530, seal 532, side walls 518
and first wall 514, as best seen in FIG. 32.
[0176] An intake port 550 connects the vacuum chamber 540 to the
socket cavity 62, as best seen in FIG. 34. This connection can be
made in any suitable way, but preferably is made by vacuum tube
76.
[0177] An exhaust port 552 connects the vacuum chamber 540 to
atmosphere.
[0178] The third embodiment may also include a shock absorber 560
to absorb shock to the wearer of the residual limb caused by
ambulation.
[0179] In one embodiment, the shock absorber 560 further comprises
a spring 562 adapted to be compressed under the weight of the
wearer of the artificial limb. The spring may be adjustable by
adjustment screw 563 to set the amount of shock absorption.
[0180] The shock absorber 560 may also comprise a compression
chamber 564 filled with a fluid, the fluid in the compression
chamber 564 being adapted to be compressed by the piston 530 under
the weight of the wearer of the artificial limb. In one embodiment,
the compression chamber 564 is formed by the piston 530, the seal
532, the side walls 518 and the second wall 516, and the fluid that
is being compressed is air. The maximum compression of the fluid in
the compression chamber may be adjustable by the user to set the
amount of shock absorption. For example, compressed air may be
introduced into the compression chamber 564 at a particular
pressure by the use of tank valve 566.
[0181] As the wearer brings his body weight to bear on the cylinder
head 513 (which is connected to the socket 60), the piston 530
travels upwardly as shown by the arrows, compressing both the air
in the compression chamber 564 and the spring 562, as best seen in
FIG. 32. At the same time, the volume of the vacuum chamber 540 is
increasing, pulling air from the socket cavity 62 through the
vacuum hose 76 and through a one-way check valve 551 into the
vacuum chamber 540 through the intake port 550.
[0182] As the wearer removes his body weight from the cylinder head
513, the now compressed air in the compression chamber 564 and/or
the compressed spring 562 forces the cylinder head 513 and cylinder
upwards toward the socket 60, so that the piston 530 travels
downwardly as shown by the arrows in FIG. 33. This action decreases
the volume of the vacuum chamber 540, expelling the air in the
vacuum chamber 540 to atmosphere through a one-way valve 553 and
exhaust port 552.
[0183] A fourth embodiment of a weight-actuated vacuum pump is
shown in FIGS. 35-38.
[0184] The fourth embodiment of the pump 610 comprises a cylinder
612 having a first wall 614, a second wall 616 and side walls 618.
The first wall 614, second wall 616, and side walls 618 enclose a
chamber 620 therein. The chamber 620 may be filled with air.
[0185] A piston 630 reciprocates within the cylinder 612, in
chamber 620. A seal 632 is placed between the piston 630 and the
cylinder side walls 618.
[0186] As the piston reciprocates within the cylinder 612, a vacuum
chamber 640 is formed by the piston 630, seal 632, side walls 618
and first wall 614, as best seen in FIG. 36.
[0187] An intake port 650 connects the vacuum chamber 640 to the
socket cavity 62, as best seen in FIG. 39a. This connection can be
made in any suitable way, but preferably is made by vacuum tube
76.
[0188] An exhaust port 652 connects the vacuum chamber 640 to
atmosphere. The intake port 650 and 652 may be the same, with
external one-way valves (not shown) to prevent unwanted
airflow.
[0189] The fourth embodiment may also include a shock absorber 660
to absorb shock to the wearer of the residual limb caused by
ambulation.
[0190] The shock absorber 660 may comprise a compression chamber
664 with wall 666, filled with a fluid. The fluid may be air or
hydraulic fluid. A second piston 634 reciprocates within the
chamber 664. The second piston 634 has a seal 636. The second
piston 634, seal 636, and wall 666 form an overflow chamber 668.
The maximum compression of the fluid in the chamber 664 may be
adjustable by the user to set the amount of shock absorption. For
example, needle valve 670 may adjustable by valve adjustment 680 to
limit the flow of fluid from chamber 664 to chamber 668.
[0191] As the wearer brings his body weight to bear on the piston
630 (which is connected to the socket 60), the piston 630 travels
downwardly as shown by the arrows, as best seen in FIGS. 36 and 37.
This causes the volume of the vacuum chamber 640 to increase,
pulling air from the socket cavity 62 through the vacuum hose 76
and through an external one-way check valve (not shown) into the
vacuum chamber 640 through the intake port 650. Simultaneously, air
in chamber 620 is compressed by the downward motion of the piston
630.
[0192] At the same time, the second piston 634 moves against the
fluid in chamber 664. Under the force of the second piston 634,
fluid is forced out of chamber 664 through needle valve 670 into
overflow chamber 668, providing a shock absorbing effect, the
extent of which is regulated by the needle valve 670.
[0193] As the wearer removes his body weight from the piston 630,
the now compressed air in chamber 620 forces the piston 630 upwards
toward the socket 60 as shown by the arrows in FIG. 38. This action
decreases the volume of the vacuum chamber 640, expelling the air
in the vacuum chamber 640 to atmosphere through a one-way check
valve (not shown) and exhaust port 652.
[0194] At the same time, fluid is forced out of overflow chamber
668 through the needle valve 670 into chamber 664, providing a
dampening effect against abrupt motion of the piston 630.
[0195] FIGS. 39a and 39b show that the fourth embodiment 610 may be
used with an artificial foot F attached to the socket 60, to
provide a mechanical vacuum pump and shock absorber.
[0196] FIGS. 40 and 41 show that the fourth embodiment 610 may be
used with an above-the-knee artificial limb 10 to provide a
mechanical vacuum pump and shock absorber. In the above-the-knee
artificial limb 10, the socket 60 is connected to a joint J that
pivots, simulating the motion of a knee joint. When weight is
applied to the joint as shown in FIG. 40, weight is transferred to
the pump 610, which draws air from the socket cavity 62 into the
vacuum cavity 640 as described above. Then, as the wearer moves his
other leg forward, the joint J pivots, allowing the knee to bend
and allowing the pump 610 to exhaust air from the vacuum chamber
640 as previously described.
[0197] The present invention may be embodied in other specific
forms without departing from the spirit or essential attributes
thereof, and it is therefore desired that the present embodiment be
considered in all respects as illustrative and not restrictive,
reference being made to the appended claims rather than to the
foregoing description to indicate the scope of the invention.
* * * * *